Rhodium-Catalyzed Asymmetric [2 + 2 + 2] Cycloaddition of Unsymmetrical α,ω-Diynes with Acenaphthylene
作者:Yukimasa Aida、Yu Shibata、Ken Tanaka
DOI:10.1021/acs.joc.7b03042
日期:2018.3.2
It has been established that a cationic rhodium(I)/(R)-BINAP complex catalyzes the asymmetric [2 + 2 + 2] cycloaddition of unsymmetrical α,ω-diynes with acenaphthylene at room temperature to give the corresponding chiral multicyclic compounds with high yields and ee values. Interestingly, enantioselectivity highly depended on the structures of α,ω-diynes used. The structural requirements of α,ω-diynes
Sequential Gold-Catalyzed Carbene Transfer/Ring Closure: Oxidative Cyclization of β-(2-Alkynylphenyl)-α,β-ynones to Indenofuranones
作者:Navnath Rode、Fabio Marinelli、Antonio Arcadi、Tapas Adak、Matthias Rudolph、Frank Rominger、A. Stephen K. Hashmi
DOI:10.1002/adsc.201801082
日期:2018.12.21
β‐(2‐Alkynylphenyl)‐α,β‐ynones undergo a gold‐catalyzedoxidative two‐fold cyclization in the presence of N‐oxides to give 1,3‐disubstituted‐8H‐indeno[1,2‐c]furan‐8‐ones in good yields. This cascade process is triggered by a selective oxygen transfer from an N‐oxide onto the gold‐activated alkynone to generate a α‐dioxocarbene intermediate which, via carbene transfer across the remaining alkyne moiety
Cobalt-catalyzed asymmetric sequential hydrogenations of conjugated enynes have been developed. The precise synthesis of chiral Z-allylamides has been realized in high activity (up to 1000 S/C) and with excellent enantioselectivity (up to >99 % ee). Mechanism experiment and theoretical calculation supported a reasonable cationic CoI/CoIII redox catalytic cycle, and explained the difference in reactivity
已经开发了钴催化的共轭烯炔的不对称顺序氢化。手性Z-烯丙基酰胺的精确合成已实现高活性(高达 1000 S/C)和出色的对映选择性(高达 >99% ee)。机理实验和理论计算支持合理的阳离子 Co I /Co III氧化还原催化循环,并解释了 Ph-BPE-Co 和 QuinoxP*-Co 之间反应性的差异。